1. Field of the Invention
The present invention relates to the field of liquid crystal display technology, and in particular to a GOA circuit and a liquid crystal display device.
2. Description of Related Art
Liquid crystal display (LCD) devices have gradually replaced cathode ray tube (CRT) display devices and have been widely used in various electronic products due to their many advantages such as small-size and light-weight, energy saving, lower radiation level than the CRT display devices. Nowadays, the driving of horizontal scan lines of an active type LCD panel mainly is completed/performed by an externally connected IC of the panel, and the externally connected IC can control charging and discharging of the horizontal scanning lines stage by stage. A GOA (gate driver on array) technology uses a TFT (Thin Film Transistor) liquid crystal display array process to fabricate a circuit of line scan drive signal Gate on an array substrate, so as to achieve the progressive scanning drive of Gate, and therefore it can utilize the original/existing manufacturing process of liquid crystal display panel to form the drive circuit of horizontal scan lines around a display area on a substrate. The GOA technology can eliminate the bonding process step associated with the externally connected IC, improve productivity and reduce production costs, and make the LCD panels be more suitable for the narrow border or no border display products.
A main structure of the GOA circuit includes: a pull-up circuit, a pull-up control circuit, a transfer circuit, a pull-down circuit, a pull-down sustain circuit, and a boost (bootstrap) capacitor responsible for the potential boost-up. In the prior art, in the transfer circuit and the pull-up circuit of the GOA circuit, a CK (clock signal) mainly is used as an output source of a scan drive signal and a stage-transfer signal, but the CK, after passing through a COF (chip on film) and reaching to the GOA wire, the signal delay in itself is very serious, which not only affects the stage shift of GOA but also affects the output quality of scan drive signal at the expense of a certain charging ratio. A commonly used method for relieving the CK delay is widening the CK, but this will increase the border width of LCD device.